Intravascular treatment has been carried out by using a highly functional catheter such as a balloon catheter, a stent, or the like. An imaging apparatus for diagnosis such as an optical coherence tomography (OCT) apparatus has been generally used in order to perform preoperative diagnosis or to check postoperative progress.
The optical coherence tomography apparatus includes a built-in optical fiber, to a distal end of which an imaging core having an optical lens and an optical mirror is attached. At least a distal end portion of the optical fiber has a transparent sheath. Then, the sheath is inserted into a blood vessel of a patient. While the imaging core is rotated, light is emitted to an intravascular wall via the optical mirror. The reflection light from the blood vessel is received again via the optical mirror, and radial scanning is performed, thereby configuring a cross-sectional image of the blood vessel, based on the obtained reflection light. Then, while the optical fiber is rotated, a pulling operation (generally called pull-back) is performed at a predetermined speed, thereby forming a three-dimensional image of an inner wall in the longitudinal direction of the blood vessel (refer to JP-A-2007-267867). In addition, as an improved OCT type, a swept-source optical coherence tomography (SS-OCT) apparatus utilizing wavelength sweeping has also been developed.
An important point in examining the postoperative progress after the stent indwells the blood vessel can be to check how closely a vascular lumen surface is in contact (familiar) with the stent. However, when the three-dimensional image is used to display the postoperative progress, a diagnostician has to check the three-dimensional image by setting various viewpoint positions, thereby causing a relatively complicated operation. In addition, whenever the viewpoint position is changed, the diagnostician has to perform a calculation for generating the three-dimensional image, which can be observed from the changed viewpoint position. Consequently, a high-level response to a user's operation cannot be expected.